The mission of the Clinical Core is to provide the personnel, facilities, and organizational structure necessary to generate the clinical database and collect patient specimens for Projects 1,2,3,4, and 5. These resources will support individual protocols within the Core, facilitate interactions between investigators, and provide a cohesive framework for the formulation, execution, and data analysis of clinical research projects. The clinical protocol is designed to utilize the best strategies currently available for diagnostic assessment and management of acute lung injury (ALl) and acute respiratory distress syndrome (ARDS). Specific aims are: 1. To manage the clinical studies involving patients with ALI/ARDS including: a) Identify eligible patients, obtain informed consent, enroll and follow patients in a standardized protocol b) Collect clinical data to provide characterization of case mix, severity of illness, and risk stratification c) Prospectively classify patients into etiologic subgroups of ALI/ARDS d) Ensure patient safety through protocol compliance, study monitoring and reporting to the Institutional Review Board (IRB) and the Data Safety Monitoring Board (DSMB) 2. To procure cells and biological fluids for individual investigators: a) Perform bronchoaiveolar lavage (BAL) and blood collection in patients with ALI/ARDS, in ventilated patients without lung injury and in normal volunteers 3. To manage a clinical study utilizing GM-CSF in ARDS patients three days post meeting ALI/ARDS criteria: a) Identify eligible patients, obtain informed consent, enroll and follow patients b) Safely store, prepare and administer GM-CSF to patients randomized to receive study drug c) Ensure patient safety through protocol compliance, study monitoring and reporting to the institutional Review Board (IRB) and the Data Safety Monitoring Board (DSMB) 4. To provide data management services to individual investigators: a) Organize and manage the clinical database b) Advise on study design, sample size calculations and selection of appropriate outcome variables c) Allow etiologic subgroup specific interpretation of molecular biologic data d) Assist with statistical applications and data analysis.